Post 32 - Rig tweaks Two: Muscle deformations & driven key techniques

I have been recently looking into a series of techniques for creating muscle deformations. In the Max rig, stretchy bones were used and then partially skinned. This worked rather well and helped to correct some mesh issues. The first method I did was by modelling a bicep and tricep, parent constrain it to the arm, and then set a series of driven keys. So when the forearm was rotated inwards, the bicep would flex and the tricep would stretch. This worked very well and can be seen working in the link below. I later on found that there is a tool in Maya specifically used to model muscles. 

I am very pleased at this point as it uses the same method as I was experimented with, so worked it out for myself using my intuition. The main difference with the the muscle tools is that instead of setting driven keys, this has been replaced with a simple squash, stretch and relaxed button selection. This technique is very interesting, but I decided that this could be a another project in itself, so I have opted to just manipulate the biceps, using set driven keys in a different way. I have parented a helper node to the arm, then set a series of driven keys so that when the forearm is rotated inwards, the helper moves what from the arm. Then, by adding the helper to the skin as an 'influential object, it essentially pulls the bicep geometry and simulates a muscle flex. This technique is quick to set up and very logical.






Initial NURBS modelled muscle with driven transform keys experiment clip - LINK
Maya Muscle tool video LINK
Chosen locator muscle deformation strategy clip - LINK